The use of liquid triglyceride fats to replace solid fats is highly desirable in that the liquid fats contain a substantial level of unsaturated and polyunsaturated fatty acids. The preparation of a margarine-type tablespread from liquid triglyceride fats is highly desirable. More particularly, it would be most desirable to replace the usual triglyceride fats used in the preparation of margarine-type tablespreads with a non-digestible liquid fat such as polyol fatty acid polyesters.
Polyol fatty acid polyesters, and in particular, the sugar fatty acid polyesters, such as, e.g., the sucrose fatty acid polyesters, are known as suitable low calorie fat replacers in edible products. Substantially indigestible for human beings, they have physical and organoleptic properties very similar to triglyceride oils and fats conventionally used in edible products. Polyol fatty acid polyesters are also reported to have use as pharmaceutical agents, e.g., in view of their ability to take up fat soluble substances such as in particular, cholesterol, in the gastrointestinal tract, and subsequently removes those substances from the human body. Accordingly, it is attractive to replace at least part of the fat in edible fat-containing products by polyol fatty acid polyesters.
It is further reported that in food products the use of polyol fatty acid polyesters which are liquid at body temperature, may give rise to the so-called problem of anal leakage. Accordingly, it is particularly attractive to replace the more solid part (hardstock) of the fat by counterpart polyol fatty acid polyesters.
In this specification, unless otherwise indicated, the term "fat" refers to edible fatty substances in a general sense, including natural or synthesized fats and oils consisting essentially of triglycerides such as, for examples, soybean oil, sunflower oil, palm oil, coconut oil, fish oil, lard and tallow, which may have been partially or completely hydrogenated or modified otherwise, as well as non-toxic fatty materials having properties similar to triglycerides, which materials may be indigestible, such as for example, waxes, e.g., jojoba oil and hydrogenated jojoba oil and polyol fatty acid polyesters referred to hereinafter in more detail. The terms fat and oil are used interchangeably.
In this specification, the term "polyol" is intended to refer to any aliphatic or aromatic compound which comprises at least four free hydroxyl groups. Such polyols in particular include the group of sugar polyols, which comprise the sugars, i.e., the mono-, di- and polysaccharides, the corresponding sugar alcohols and the derivatives thereof having at least four free hydroxyl groups. Examples of sugar polyols include glucose, mannose, galactose, xylose, fructose, sorbose, tagatose, ribulose, xylulose, maltose, lactose, cellobiose, raffinose, sucrose, erythritol, mannitol, lactitol, sorbitol, xylitol and alpha-methylglucoside. A generally used sugar polyol in sucrose.
In this specification, the term "polyol fatty acid polyester" is intended to refer to any such polyesters or mixtures thereof, of which, on an average, more than 70% of the polyol hydroxyl groups have been esterified with fatty acids.
In this specification, by "indigestible" is meant that at least about 70% by weight of the material concerned is not digested by the human body.
In this specification, by "hardstock" is meant that part of the fat composition characterized by a slip melting point of above 36.degree. C. "Slip melting point" is defined as the temperature at which the amount of solid phase in the melting fat has become to low that an air bubble is forced upwards in an open capillary filled with the fat.
Fat-containing products and in particular, emulsion-type products such as margarines and low-fat spreads, have to comply with requirements such as oral response, thermal stability, cycle stability, spreadability, melting behavior and the like. Often they have to comply with such requirement simultaneously.
In particular, for margarines and low-fat spreads which contain relatively large amounts of polyunsaturated components, or require increased softness at lower (refrigerator) temperatures, it can be difficult to simultaneously comply with the requirements for cycle stability, thermal stability and acceptable taste properties.
Stability against temperature changes (cycle stability) is important in view of temperature changes during transport and storage as well as temperature changes which may frequently occur during household use. Improved storage temperature cycle stability is therefor advantageous, if not essential.
Heat stability, i.e., stability in terms of the absence of phase separation and of oil exudation, determines the ambient temperatures at which the product can be used. It will be clear that heat stability requirements are dependent of the climatic zone involved.
In general, the heat stability is governed by the amount of hardstock, i.e., the amount of higher melting fats. A better heat stability, however, in general will result in a deterioration of the oral response, especially after temperature cycling. This is because the oral response largely depends on the melting behavior of the fat phase.
Although not wishing to be bound by theory, it is believed that the difficult compatability of heat stability, good oral response and cycling stability stems from the fact that good heat stability (e.g., heat stability at 30.degree. C. for 24 hours) generally requires fat blend compositions containing relatively high amounts of higher melting fat fractions such as in particular, fat fractions having melting points above mouth temperature. These higher melting fat fractions are believed to be responsible for the adverse effects on oral response and cycling stability.